M14 Forum banner
Status
Not open for further replies.

Benefits of shooting limited quantities of steel jacketed ammo through a new barrel?

4K views 27 replies 12 participants last post by  XXIV Corps 
#1 ·
I have a bias against using "steel" ammo in anything expect an AK; and I don't have an AK. That said, I deliberately purchased 100 rounds of steel jacketed 7.62 x 51 ammo to shoot through my new M1a Scout. Here is why:

I bought a new Ruger Super Blackhawk .44 Mag single action revolver in 1982. It turned out super accurate and did not lead the barrel at all with hard cast bullets. The cheapest reloadable factory ammo I could buy at the time was 400 rounds of Norma softnose. These happened to have copper washed steel jackets.

My theory is that, because I first shot 200 rounds of steel bullets through the Ruger, the barrel was "burnished" before I shot any lead through it.

The idea is that any high spots down the barrel would have been "pushed in" or "worn down" more by the steel bullets, ensuring a parallel bore, or one that tapers down slightly towards the muzzle.

Not only would the bore have been smoother, but the "hard" steel bullets would tend to result in a barrel that was ever so slightly "wider" at the breech than at the muzzle. The lands or land corners would effectively taper slightly towards the muzzle, so they were always in hard contact with the bullets, all the way out the muzzle.

All I know is that the Ruger would shoot 2" groups at 25 yards using a two handed grip, with me standing unsupported on my hind legs. I don't know what it would do over sand bags, but it was plenty accurate for metallic silhouette shooting.

I am planning to shoot some NATO steel jacketed ammo through my M1a to burnish the barrel, or at least smooth out the leade ahead of the chamber. The reason why this may work is precisely because "steel ammo will wear out your barrel faster". However, I don't plan to shoot more than 100 rounds before a diet of copper only.

Does anyone one see any merit in shooting a limited quantity of "steel" ammo from a new barrel; rather than just looking at it as not doing much harm?

These guys shot 10,000 rounds of steel ammo at very high continuous rates from AR15s, and compared the wear against copper jacketed bullets. The accurate barrel life, shooting steel, was half that for copper; under these conditions: http://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/
 
See less See more
#2 ·
I understand your thoughts about 'burnishing' the bore, but your assumption seems to be that the bullet's shape is more precise than the bore.

My guess is that those bullets were made to be cheap, rather than made to be good for the results you want.

Jay Kosta
Endwell NY USA
 
#9 · (Edited)
Bullets may not be made "round" or consistent in diameter, but they enter the bore in random orientation, so how they wear the barrel tends to even out over multiple rounds.

A bullet gets thumped pretty hard from behind at peak pressure, so it upsets or rivets to fill the bore. If the bore is round, so is the bullet...

How much a bullet upsets depends on how stiff the bullet is and how abruptly the pressure rises.
 
#10 · (Edited)
A steel bullet may not be as hard as the barrel, but the propellant and primer residues trapped between them are mildly abrasive; so there is your "lap". The same residues trapped between a harder steel jacket will probably polish the barrel faster than a copper jacketed bullet.

As the contact between bullet and barrel is greatest near the start of its travel due to highest gas pressure, it seems reasonable that that is where the friction induced wear would be highest.

If the bore has tight spots in it, the contact pressure between bullet and barrel will go up there, and not where the barrel is loose.

Higher contact pressure with abrasive firing residues should produce higher wear where it "needs it; thus evening out the barrel and generally wearing more at the breech than the muzzle.
 
#11 · (Edited)
You can't scratch a file with a nail, but you can wear a file out, filing multiple nails. A barrel is half as hard as a file, while a steel bullet jacket is probably close to a mild steel nail in hardness.

Again; it is the firing residue that is actually causing the wear due to its abrasive nature. The steel jacket is just pressing it into hard contact with the barrel.
 
#12 · (Edited)
I like standing and shooting. How many people shoot their rifles off sandbags all the time, and then boast about the smallest group they ever shot (not typical groups)? Sandbags are for checking equipment, or for sighting in - not much skill required, unless it is at extreme range. If you can shoot fairly well standing, then other positions are relatively easy...
 
#13 ·
I think what I am suggesting works very much like fire lapping with abrasive; except the abrasive is much finer (firing residue). I know that terribly rough barrels benefit from fire lapping with 300 grit abrasive. Accuracy is improved and they clean easier. I also know that fire lapping preferentially opens up the throat and can shorten the accurate life of a barrel that was good to begin with.

As steel jacketed NATO ammo is common, what I am proposing is not nearly so far out. I am just shooting surplus ammo; but instead of avoiding steel jacketed rounds, I am deliberately shooting a small number of them early on.
 
#7 ·
I do not know what sort of precision on target you need. I can tell you I never knew of any Highpower competitor who did anything with a new barrel on a Match Conditioned M1A but shoot his normal match ammo thru it.

The minimum standard for these rifles was keeping 20 shots in a 12" 10-ring at 600 yards with half of them in a 6" X-ring. This from prone with a sling and iron sights.

There are commercially available barrel break-in "systems" out there which are bullets coated with valve grinding compound.

You could do it yourself with a cleaning rod, patches and JB Bore Paste.

If you do not have access to a bore scope how will you know what is happening to the bore?

All things considered, lapping bores is probably over the top for a service rifle.
 
#14 · (Edited)
You are correct that I don't know the condition of my Scout's barrel. Therefore "fixing" it in any aggressive manner that is not born out by real evidence would be silly. Large group size with my rifle are probably due to cheap ammo and a floppy plastic stock; to a much larger degree than barrel bore condition.

Lapping a finished barrel by hand is not something I would advocate, unless the barrel was behaving very badly. Then tight spots could be lapped by a person who knows what they are doing. This would require casting lead laps in the bore, and replacing them as soon as the previous lap has worn "loose". Lapping compound applied to a patch is a recipe for rounding off the land corners, because that is where the contact pressure is highest.

Careless lapping tends to bell the bore where the lap turns around. The neophyte would tend to wear a bell near the muzzle and just ahead of the chamber, ruining the barrel.

However, shooting surplus ammo that happens to have steel jackets should not be nearly as risky as amateur hand lapping of an installed barrel.
 
#15 ·
This would apply to hand lapping a barrel that did not absolutely need it. First do no harm.

Who hasn't seen a factory barrels improve in accuracy during the first few hundred rounds? If this is how long it takes with copper jackets, then steel jackets may reach that point with half as many rounds fired.

That 50% is extrapolated from the article on shooting 10,000 steel VS copper jacketed 5.56 x 45 rounds. That test indicated that accurate barrel life with steel jacketed ammo was half that with copper bullet jackets...

Back to the beginning: I have no way of knowing if my Super Blackhawk would have been just as accurate or better with copper jacketed rounds only. What I can say is that 400 rounds of steel jacketed ammo did it no apparent harm. Selling that revolver is one of my biggest regrets...
 
#18 ·
There is absolutely nothing positive that comes from shooting steel jacketed ammo through your rifle. Gauges and bore scopes do not lie. If there was any benefit to it - other than saving a few bucks, it would be easy to find those that trumpet the gift of steel jacketed ammo.
It was perfectly stated earlier - Barrels wear out fast enough with normal shooting. Why rush it?
If your were to document the throat of your barrel when new then take a comparative picture / measurements after 200 or 300 rds - trust me - you'd never do it again.

Look at it from this perspective - handguns that shoot a steady diet of lead take forever to wear out a barrel. Now compare the erosion rates to barrels that shoot only copper jacketed ammo. All averaged out - you are looking at easily 30-40% less usable life. Why would you want to put an even harder bullet into your barrel?

Heat and pressure are the culprits of throat erosion. Don't aid the process by adding a hammer.

On top of it all - I would bet you that SAI would void any warranty knowing that you fed it steel ammo.

Just sayin...
 
#21 ·
There is absolutely nothing positive that comes from shooting steel jacketed ammo through your rifle.


On top of it all - I would bet you that SAI would void any warranty knowing that you fed it steel ammo.
SA may frown on shooting Tula steel cased ammo, but they don't want me shooting Federal NATO ball ammo? NATO ammo is sometimes made with steel jackets. I bet a bunch of you have shot it without knowing because the bullets look like copper.

I will write SA customer service and ask them about shooting such NATO ammo, and report back.

This guy shot 7000 rounds of mostly steel cased ammo through his Scout, and reports no loss in accuracy. Then again, he is not shooting tiny groups at hundreds of yards: [ame]https://www.youtube.com/watch?v=HAfN5FNuo_0[/ame]
 
#28 ·
This horse is done for it Gentlemen.

GI5
 
  • Like
Reactions: nf1e
Status
Not open for further replies.
You have insufficient privileges to reply here.
Top